NIGHT VISION TECHNOLOGY A SEMINAR REPORT

[seminar class]

presented by:
Y. Shiva kumar

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NIGHT VISION TECHNOLOGY
Introduction:
 NVT allows us to see in the dark
 Originally developed for military use
 Now used for site security, surveillance as well as search and rescue
 Evolved from bulky optical instruments in lightweight goggles through the advancement of image intensification technology.
Types of night vision:
 Categorized by generations
 Each substantial change NVT establishes a new generation
 Categorized into:
Generations- 0 , 1, 2 , 3 , 4 .
Generation-0:
 Created by US Army
 Uses active infrared
 A projection unit called IR illuminator is attached
 Full moon operation
 Use anode in conjunction with cathode to accelerate the electrons
 Problems –acceleration causes distortion of image as well as reduction of life of the tube
 Also, it was quickly duplicated by the hostile nations
Generation-1 (1960’s):
 Uses passive infrared
 Uses ambient light provided by the moon and the stars
 Don’t require a source of projected infrared light
 Don’t work well on cloudy or moonless nights
 One quarter moon operation
 Uses same image-intensifier tube technology as Generation-0
 Same problems as faced by the Generation-0
Generation-2 (1970’s)
 Offer improved resolution and performance over Generation-1 devices
 Considerably more reliable
 Able to see in extreme low light conditions due to the addition of microchannel plate(MCP) to the image-intensifier tube
 The images are less distorted and brighter
Generation-3 (1990’s)
 Currently used by the US Army
 Better resolution and sensitivity
 Photocathode is made up of Gallium Arsenide
 MCP is coated with an ion barrier
 Tube life is increased
Generation-4 (2000’s)
 Known as “filmless and gated” technology
 Shows significant improvement in both high- and low-level light environments
 No ion barrier in MCP
 Responds quickly to different lightning conditions
 Reduced background noise
 Enhances signal to noise ratio
 Images are less distorted and brighter
Thermal imaging
 This technology operates by capturing upper portion of the infrared light spectrum, which is emitted as heat
 Hotter objects emit more of this light than the cooler objects
 These elements then create a thermogram
 Thermogram àelectric pulsesà display data